Cande Ananth

Epidemiology of twinning in developed countries.

Twin births contribute disproportionately to the overall burden of perinatal morbidity and mortality in developed countries. Twins constitute 2%-4% of all births, and the rate of twining has increased by 76% between 1980 and 2009. The rate of preterm birth (<37 weeks) among twins is about 60%. Of all twin preterm births in the United States, roughly half are indicated, a third are due to spontaneous onset of labor, and about 10% are due to preterm premature rupture of membranes. Mortality related to preterm birth is influenced by antecedent factors and is highest when preterm delivery is the consequence of preterm premature rupture of membranes, followed by those as a result of spontaneous preterm labor and lowest among indicated preterm births. There also appears to have been a recent decline in serious neonatal morbidity (one or more of 5-minute Apgar score <4, neonatal seizures or assisted ventilation for ≥ 30 minutes) among twin gestations. Compared with twins conceived naturally, those born of assisted reproduction methods are more likely to deliver at <37 weeks. Although perinatal mortality rates have declined among twin births, the effect of preterm delivery on trends in mortality and morbidity and other long-term consequences remain issues for major concern. With the rapid increase in the liberal use of assisted reproduction methods combined with women electing to postpone their pregnancies and increased likelihood of spontaneous twins with advancing maternal age, this review underscores the need to develop priorities to understand the peripartum and long-term consequences facing twin births.

Ischemic placental disease: epidemiology and risk factors

OBJECTIVEnPreeclampsia, small for gestational age (SGA) and placental abruption - conditions that constitute the syndrome of ischemic placental disease (IPD) - may portend different clinical manifestations of a common underlying pathophysiology. We examined if (i) preeclampsia, SGA and abruption share similar risk profiles; and (ii) if there are any differences in these profiles between patients with IPD that delivered at term and preterm gestations.nnnSTUDY DESIGNnWe utilized data from the US Collaborative Perinatal Project, a multicenter, prospective cohort study (1959-1966), restricted to women that delivered singleton births at ≥ 20 weeks (n=47,495.) We compared risk factors between women with and without IPD as well as preeclampsia, SGA and abruption.nnnRESULTSnA strong overlap in risk factors for all 3 conditions was evident. Socio-economic class, income, age, parity, education, race, BMI, marital status, and history of preterm birth were different between preterm and term gestations in women with IPD. Although rates of preeclampsia only, SGA only and preeclampsia with SGA were similar between term and preterm birth, rates of other conditions were higher at preterm gestations, with abruption being the driving condition behind these associations.nnnCONCLUSIONSnThe similar risk profiles for preeclampsia, SGA, and abruption provide compelling evidence to suggest that these conditions may share common pathophysiological mechanisms-ischemic placental disease. Greater homogeneity in risk profiles within preterm than term births suggests that IPD may be a syndrome that has strong underpinnings at preterm gestations.

Domestic abuse in pregnancy: A comparison of a self-completed domestic abuse questionnaire with a directed interview☆☆☆

OBJECTIVEnThe purpose of this study was to compare the results of a standardized self-completed domestic abuse questionnaire with those of a directed interview in the identification of domestic abuse in pregnant patients.nnnSTUDY DESIGNnAll patients with a first prenatal visit between March 1 and September 30, 1997, were assessed for self-reported domestic abuse with a standardized domestic abuse questionnaire. This was followed by a directed interview that involved verbal review of the standardized domestic abuse questionnaire. Self-reported domestic abuse was defined as any positive response to the domestic abuse questionnaire or the directed interview. The number of patients with a positive response to either the standardized questionnaire or the directed interview, or both, were recorded. The 2 techniques were compared by the McNemar chi(2) test. The group demographics and characteristics were evaluated.nnnRESULTSnAmong the 224 patients evaluated, a total of 36% (n = 80) of the patients reported domestic abuse by either method. The standardized domestic abuse questionnaire identified 85% (n = 68) compared with 59% (n = 47) by a directed interview (P =.03). The use of the standardized domestic abuse questionnaire and the directed interview in parallel identified an additional 15% (n = 12) of patients with domestic abuse.nnnCONCLUSIONnA standardized domestic abuse questionnaire is superior to a directed interview in identifying self-reported domestic abuse in pregnancy. Utilizing both methods in parallel further increases the number of patients identified.

Induction of Labor in the United States: A Critical Appraisal of Appropriateness and Reducibility

Approximately 1 in 4 women in the United States are induced, with up to 1 in 10-12 being induced for elective reasons. National guidelines by the American College of Obstetricians and Gynecologists, the Society of Obstetricians Gynaecologists of Canada, and the Royal College of Obstetricians and Gynaecologists list 21 indications for inductions; however, all 3 concur in only 14% women (3 of 21). An induction should be considered appropriate if it meets the following 4 criteria: (1) concordant with womens autonomous informed decisions and desideratum; (2) optimizes maternal-fetal outcomes, including psychological maternal well-being; (3) congruous with evidence-based medicine; and (4) cost-effective. A meta-analysis of 22 randomized trials noted that membrane sweeping reduces the likelihood of induction. Implementing policies to prevent elective induction at 37-38 weeks provides conflicting results about the rate of macrosomia and stillbirth at early term. We argue that a well-designed randomized controlled trial, with adequate power to demonstrate whether prohibiting elective induction increases the rate of stillbirth or complications such as macrosomia, is warranted. Patient education during their prenatal course is a promising strategy to decrease the rate of induction.

Neonatal respiratory morbidity in the early term delivery.

OBJECTIVEnThe purpose of this study was to evaluate the risk of respiratory morbidity in neonates delivered at early term (37-38 weeks) compared with those delivered at 39 weeks.nnnSTUDY DESIGNnWe conducted a retrospective cohort study of singleton deliveries from 37(0/7) to 39(6/7) weeks gestation. Our primary outcome was composite respiratory morbidity.nnnRESULTSnOf 2273 deliveries at 37-39 weeks, 51% (n = 1169) delivered in the early term period. Infants delivered at 37-38 weeks had a 2-fold increased risk of respiratory distress syndrome, oxygen use, continuous positive airway pressure use, and composite respiratory morbidity (risk ratio [RR], 2.9; 95% confidence interval [CI], 1.0-7.9; oxygen usage RR, 2.0; 95% CI, 1.4-2.9; continuous positive airway pressure RR, 1.9; 95% CI, 1.1-3.2; composite respiratory morbidity RR, 2.0; 95% CI, 1.4-2.8).nnnCONCLUSIONnThe 2-fold increased risk of composite respiratory morbidity of infants in the early term period supports the urgency for limiting nonindicated deliveries to ≥ 39 weeks gestation.

Measuring the compressive viscoelastic mechanical properties of human cervical tissue using indentation

The human cervix is an important mechanical barrier in pregnancy which must withstand the compressive and tensile forces generated from the growing fetus. Premature cervical shortening resulting from premature cervical remodeling and alterations of cervical material properties are known to increase a woman׳s risk of preterm birth (PTB). To understand the mechanical role of the cervix during pregnancy and to potentially develop indentation techniques for in vivo diagnostics to identify women who are at risk for premature cervical remodeling and thus preterm birth, we developed a spherical indentation technique to measure the time-dependent material properties of human cervical tissue taken from patients undergoing hysterectomy. In this study we present an inverse finite element analysis (IFEA) that optimizes material parameters of a viscoelastic material model to fit the stress-relaxation response of excised tissue slices to spherical indentation. Here we detail our IFEA methodology, report compressive viscoelastic material parameters for cervical tissue slices from nonpregnant (NP) and pregnant (PG) hysterectomy patients, and report slice-by-slice data for whole cervical tissue specimens. The material parameters reported here for human cervical tissue can be used to model the compressive time-dependent behavior of the tissue within a small strain regime of 25%.

Use and attitudes of obstetricians toward 3 high-risk interventions in MFMU Network hospitals.

OBJECTIVEnWe sought to evaluate the frequency of, and factors associated with, the use of 3 evidence-based interventions: antenatal corticosteroids for fetal lung maturity, progesterone for prevention of recurrent preterm birth, and magnesium sulfate for fetal neuroprotection.nnnSTUDY DESIGNnA self-administered survey was conducted from January through May 2011 among obstetricians from 21 hospitals that included 30 questions regarding their knowledge, attitudes, and practice of the 3 evidence-based interventions and the 14-item short version of the Team Climate for Innovation survey. Frequency of use of each intervention was ascertained from an obstetrical cohort of women between January 2010 and February 2011.nnnRESULTSnA total of 329 obstetricians (74% response rate) who managed 16,946 deliveries within the obstetrical cohort participated in the survey. More than 90% of obstetricians reported that they incorporated each intervention into routine practice. Actual frequency of administration in women eligible for the treatments was 93% for corticosteroids, 39% for progesterone, and 71% for magnesium sulfate. Provider satisfaction with quality of treatment evidence was 97% for corticosteroids, 82% for progesterone, and 57% for magnesium sulfate. Obstetricians perceived that barriers to treatment were most frequent for progesterone (76%), 30% for magnesium sulfate, and 17% for corticosteroids. Progesterone use was more frequent among patients whose provider reported the quality of the evidence was above average to excellent compared with poor to average (42% vs 25%, respectively; P < .001), and they were satisfied with their knowledge of the intervention (41% vs 28%; P = .02), and was less common among patients whose provider reported barriers to hospital or pharmacy drug delivery (31% vs 42%; P = .01). Corticosteroid administration was more common among patients who delivered at hospitals with 24 hours a day-7 days a week maternal-fetal medicine specialist coverage (93% vs 84%; P = .046), CONCLUSION: Obstetricians in Maternal-Fetal Medicine Units Network hospitals frequently use these evidence-based interventions; however, progesterone use was found to be related to their assessment of evidence quality. Neither progesterone nor the other interventions were associated with overall climate of innovation within a hospital as measured by the Team Climate for Innovation. National Institutes of Health Consensus Conference Statements may also have an impact on use; there is such a statement for antenatal corticosteroids but not for progesterone for preterm prevention or magnesium sulfate for fetal neuroprotection.

Fetal sex pairing and adverse perinatal outcomes in twin gestations

PURPOSEnTo assess the association between fetal sex pairing in twin pregnancies and adverse perinatal and infant outcomes.nnnMETHODSnA retrospective cohort study of 9770 infants from 4885 twin pregnancies delivered in 2007 was conducted with a statewide hospital discharge database for Texas. Log-binomial regression models based on generalized estimating equations were used to calculate relative risks (RR) and 95% confidence intervals (95% CI) for the following dichotomous outcomes: breech presentation, hospital mortality, intrauterine growth restriction (IUGR), low birth weight, prolonged length of stay (>4 days), receipt of mechanical ventilation, and respiratory distress syndrome (RDS).nnnRESULTSnThe sample was composed of 4918 females and 4852 males. An approximately equal number of infants were from a female-female pregnancy (n = 3270), mixed-sex pregnancy (n = 3296), and a male-male pregnancy (n = 3204). Twins of either sex from mixed-sex pairs were 45% less likely to die in the hospital compared with females from a female-female pregnancy (RR, 0.55, 95% CI, 0.31-0.98). Males from a male-male pair were 33% less likely than females from female-female pairs to experience IUGR (RR, 0.67; 95% CI, 0.53-0.83). The incidence of RDS was significantly increased in males from male-male twin pairs versus females from female-female pairs (RR, 1.21; 95% CI, 1.05-1.41).nnnCONCLUSIONSnMale infants from male-male twin pairs were more likely to develop RDS and be placed on a ventilator but less likely to experience IUGR than female infants from female-female pairs.

The early developments of preeclampsia drugs

Preeclampsia is a pregnancy-specific multisystem disorder that affects 3–5% of pregnant women [1]. It remains a major cause of maternal and neonatal morbidities and mortality, as more than 50,000 women die annually from preeclampsia worldwide, mostly in developing countries [1]. Preeclampsia is usually diagnosed based on new onset hypertension, proteinuria, or end organ damage after 20 weeks of gestation [1]. Due to lack of effective therapy for preeclampsia, and in order to prevent maternal morbidity and mortality, obstetricians tend to deliver women with preeclampsia shortly after diagnosis. However, this approach is usually associated with risk of premature delivery and its associated morbidities. Despite being a pregnancy-specific condition, preeclampsia is associated with long-term maternal and neonatal adverse outcomes, as it may predispose the mother to hypertension, cardiovascular disease including stroke and ischemic heart disease, renal disease, and premature death and the neonate to the long-term complications of preterm delivery; as well as adult metabolic, cardiovascular, and neurodevelopmental disorders [1]. Recent advances in understanding the pathogenesis of preeclampsia led to an interest in novel therapeutic and/or preventive agents for preeclampsia. These include anti-digoxin antibodies, antithrombin, relaxin, and 3-hydroxy-3-methylglutaryl-coenzymeA reductase inhibitors (statins) [2]. Discussion of all these therapeutics is beyond the scopeof this editorial, whichwill focus on the biological plausibility and current clinical trials using statins to treat and/or prevent preeclampsia.

Paternal age and risk for cesarean delivery

Objective: To determine whether advanced paternal age is associated with increased risk for cesarean delivery. Study design: We used the 1990–2002 US linked live birth and infant death data files restricted to primiparous Caucasian and African-American women that delivered a singleton birth at ≥20 week’s gestation (12.5 million). We examined temporal trends and risk ratios of cesarean birth in relation to paternal age before and after adjustments for known confounders. Results: Among Caucasians, the cesarean delivery rates were 21.1%, 26.7% and 31.8% in fathers aged 20–29, 30–39 and ≥40 years, respectively. Among African-Americans, the corresponding rates were 24.1%, 33.2%, and 38.1%, respectively. These increased cesarean delivery rates persisted in analyses stratified by maternal age before and after adjustment for a variety of confounders. Conclusions: These findings suggest that increasing paternal age may be associated with an increased risk for cesarean delivery in primiparous women.